1. Field of the Invention
The present disclosure relates to a moving body guide mechanism of a machine tool such as a horizontal machining center for supporting and guiding a moving body thereof such as a spindle in a movable manner.
2. Description of the Related Art
The following description of related art sets forth the inventors' knowledge of related art and certain problems therein and should not be construed as an admission of knowledge in the prior art.
In a horizontal machining center, as a spindle guide mechanism for supporting and guiding a spindle in a horizontally movable manner, there is one disclosed in Japanese Patent No. 4373892, for example. In this conventional spindle guide mechanism, a pair of left and right guide rails is disposed on a head that supports a spindle so as to extend in a horizontal direction. Linear guides fixed to the spindle are slidably engaged with the guide rails. A ball screw is provided between the left and right guide rails so as to extend in the horizontal direction. A nut member fixed to the spindle is screwed on the ball screw. A drive motor is coupled to one end portion of the ball screw, and the drive motor is fixed to the head.
In the conventional spindle guide mechanism, there is employed a structure in which the ball screw is disposed between the left and right paired guide rails and the drive motor is coupled to a rear end portion of the ball screw. Therefore, this ball screw or the drive motor need to be disposed apart from the axis of the spindle to such an extent that they do not interfere with the guide rails, or an interval between the guide rails needs to be increased. Therefore, there is caused a problem that the spindle guide mechanism is increased in size.
Further, when the ball screw is disposed apart from the axis of the spindle, the ball screw far from the axis of the spindle is driven, which increases the residual vibration and makes it difficult to increase acceleration. Therefore, there is also a problem that speeding up cannot be achieved.
The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. For example, certain features of the preferred described embodiments of the invention may be capable of overcoming certain disadvantages and/or providing certain advantages, such as, e.g., disadvantages and/or advantages discussed herein, while retaining some or all of the features, embodiments, methods, and apparatus disclosed therein.